1. Field of the Invention
The present invention relates to a technology of an indwelling needle comprised of a hard inner needle which punctures the skin and reaches the vein and a soft outer needle which is located outside of the inner needle and is indwelled within the vein and is directed to an indwelling needle with an inner needle retraction mechanism.
2. Description of the Prior Art
Various techniques have been proposed in order to prevent secondary infection.
For example, Japanese Patent Application Laid-Open Hei 9 No. 629 is directed to an xe2x80x98indwelling needlexe2x80x99 which aims at xe2x80x98safety disposal of the inner needle of the used indwelling needle without any risk of the workers concerned being secondarily infectedxe2x80x99 and has a xe2x80x98configuration which enables the inner needle to be fixed within the protection coverxe2x80x99.
Since a typical indwelling needle is comprised of a resin-made outer needle and a stainless inner needle, the risk of secondary infection due to xe2x80x98needlestick injuriesxe2x80x99 arises from the inner needle. Therefore, other than that disclosed in Japanese Patent Application Laid-Open Hei 9 No. 629, there are several techniques of confining the inner needle, which would cause erroneous or accidental prick, within a tubular sleeve.
In general, the tubular sleeve keeps the inner needle therein and does not retract the outer needle. With regards to the mechanism for retraction, the mechanism preferably has a device for preventing the outer needle from being drawn into the tubular sleeve even if the mechanism malfunctions during and/or after the puncture of the inner and outer needles to the patient""s skin. With this device, it is possible to secure necessary safety during the treatment and eliminate the burden on the patient due to doing over again. However, if the countermeasure against such a malfunction is attempted by devising inner needle retraction arrangements, a complex mechanism will be needed and also a troublesome operation for retraction of the inner needle will be needed.
Both the inner and outer needles are made to puncture the patient""s skin and only the inner needle is pulled out while the outer needle remains therein. When the inner needle is pulled, in order to prevent the outer needle from being removed together with the inner needle, it is necessary to apply the finger around the contact area between the outer needle and the skin and/or the proximal part of the outer needle. In this case, if any projection is present around the proximal part of the outer needle, it is not desirable for xe2x80x98the finger that is applied on the outer needle proximal partxe2x80x99 because such a projection deteriorates fastness and readiness in handling.
It is therefore an object of the present invention to provide an indwelling needle with an inner needle retraction mechanism which is capable of retracting the inner needle, disallows the outer needle to be withdrawn by any malfunction and will not reduce fastness and readiness in handling.
It is another object of the present invention to provide an indwelling needle with an inner needle retraction mechanism which provides readiness in retracting the inner needle.
In order to achieve the above objects, the present invention is configured as follows:
The present invention is directed to an indwelling needle including a hard inner needle (12), a soft outer needle (11) and an inner needle retraction mechanism. That is, the present invention relates to an indwelling needle with an inner needle retraction mechanism, has a container barrel (1) having distal and proximal ends, and having an inner needle retraction mechanism (including an actuator 6 and urging element 8) for holding the inner needle (12) after use therein; and an outer needle support lid element (20) fixed at the distal end of the container barrel (1) for prohibiting the outer needle (11) from being withdrawn into the container barrel (1), and is characterized in that the outer needle support lid element (20) has a gutter-like portion, which is a short cylinder formed in part with a cutout portion (20C) and the inside dimension thereof is designed so as to allow the inner needle (12) to pass therethrough and be smaller than the outside dimension of the hub (11a) (more exactly, a flange 11b of hub 11a) of the outer needle (11).
In accordance with the above configuration of the present invention, the outer needle (11) together with the inner needle (12) is made to puncture the skin and reach the vein. Then, the inner needle (12) is withdrawn while the hub (11a) of the outer needle (11) being held. During this procedure, since the outer needle support lid (20) has the cutout portion (20c), the finger is able to hold the hub (11a) of the outer needle (11) without any obstruction. At this point, if the retraction mechanism (6 and 8) operates, the outer needle (11) will not be withdrawn into the container barrel (1) because there exists the outer needle support lid (20) having an inside dimension smaller than the outside dimension of the hub (11a) of the outer needle (11).
After the inner needle (12) is pulled out, an fluid injection tube for injection to the patient body such as an drip infusion tube is connected to the hub (11a) of the outer needle (11).
In the present invention, the inner needle retraction mechanism may be comprised of a guide groove (2) formed in the container barrel (1) in the longitudinal direction thereof, an actuator (6) fixed to the inner needle (12) and having an actuator piece (6a) for causing the inner needle (12) to be retracted into the container barrel (1) and an urging element (8) for urging the actuator (6) to the proximal side of the container barrel (1), and the cutout portion (20c) of the outer needle support lid element (20) may be positioned in proximity to the actuator piece (6a).
In this case, since the cutout portion (20c) of outer needle support lid element (20) is positioned in proximity to the actuator piece (6a), it is possible to perform the pulling action of the inner needle (12) while holding the hub (11a) of the outer needle (11) and the action of causing retraction of the inner needle (12) into the container barrel (1), without changing the grip of the container barrel (1).